Carboxylic acid salts of n-dialkylaminoalkylamides



United States Patent Murray Jelling, Whitestone, N. Y.

Application November 19, 1953, Serial No. 393,244

Claims. (Cl. 26097.5)

No Drawing.

This invention relates to bituminous compositions of the type that aremixed with mineral aggregates in the construction of asphalt pavements.More particularly the invention relates to a novel group of bondingagents which are adapted to be incorporated in such bituminouscompositions and when so incorporated not only improve the bondingefiectiveness of the bituminous composition but also exhibit improvedthermal stability as compared with the bonding agents previously used.The present application is a continuation-in-part of my priorapplication Serial No. 196,929 filed November 21, 1950, now Patent No.2,663,648. The claims of my parent application are particularly directedto bituminous compositions containing the novel bonding agents, whereasthe claims of the present application are directed to certain of thebonding agents per so as new compositions of matter.

During the development of the art of improving the coating and bondingqualities of bituminous compositions when mixed with mineral aggregatesin the construction of asphalt pavements, several types of chemicalagents have been proposed and used. The use of these agents has made itpossible to use wet aggregates in preparing paving mixtures, therebyobviating the necessity of having available dry aggregates. Thus,attendant delays in road construction have been eliminated. Also, theincorporation of bonding agents has permitted the use of hydrophili-caggregates, which could not otherwise be employed. In addition theincorporation of these chemical bonding agents has brought about animprovement in the.struc-. tural stability of the finished bituminouspavement by increasing the resistance to separation of aggregate andbitumen caused by the detrimental action of water.-

Thus,-these agents have been useful in improving the method of asphaltroad construction and in improving the quality and length of service ofthe finished pavement.

Chemical bonding agents of several types have been proposed and used,such as metallic soaps, fatty acids, surface active amines, amine soaps,and acyl-amidoamines and their soaps. The most useful, from the point ofview of effectiveness, ease of application, and cost, have been thosebased on compositions of surface active organic amines such as describedin patents to Louis -A. Mikeska:

of storage may be as long as 14 days. As required, the asphalt iswithdrawn and handled as is or mixed. with hydrocarbon diluents inpreparing cutback asphalts.

In other instances, quantities of asphalt or like bitumen are heated ashigh as 400-500 F. at the time of shipment so that its temperature uponarrival at the point of destination will have dropped to about 300-350R, which is the desirable temperature required for proper application inpreparing the paving mixture.

It has recently become apparent that many conventional types of bondingagents lose their etfectiveness in a very short time when subjected tothese high temperatures, i. e. temperatures in the range normallyencountered with the storing and handling of bituminous materials. Whenthe above described bonding agents are subjected to these hightemperature conditions, their effectiveness is consequently lost in ashort time and they are of little value as bonding agents.

As "an example of this loss of effectiveness, samples of penetrationgrade asphalts containing a sufiicient quantity of bonding agent toproduce the desired coating, bonding, and resistance to the strippingaction of water, were maintained at 325 F. for 24 hours. When pavingmixtures were made, allowed to cure, and then immersed in water, thelack of resistance to stripping was readily apparent as compared tosimilar preparations, where the treated asphalts were not subjected to ahigh temperature, but were used in preparing the paving mixturesimmediately after adding the bonding agent. As another example, when thetreated penetration asphalts, after being maintained at 325 F. for-24hours, were converted to cutback asphalts by adding petroleum naphtha,they were ineffective in coating wet stone and forming durable bondswith aggregates. By comparison, similarly treated samples, not subjectedto the prolonged high temperature, upon conversion to cutback asphaltsin a similar manner, were efiective in coating wet stone, formingdurable bonds with aggregates, and resisting the stripping action ofwaterupon immersion of the paving mixtures in water.

In my prior application Serial No. 196,929 referred to above it wasdisclosed that the foregoing difficulties can 'be overcome by using asbonding agents certain N-dialkylaminoalkyl'amides and their carboxylicacid salts. Such bonding agents not only improve substantially thebonding eifectiveness of bituminous compositions but also aresufficiently stable thermallyto withstand the elevated temperaturesfrequently encountered in the processing of such bituminouscompositions.

Moreover, while both the amides and their salts, when incorporated inbituminous compositions which are heated at elevated temperatures forextended periods as described in my parent application, are operative toimprove the bonding efiec'tivenessof the bituminous compositions, it

No. 2,389,680, issued November 27, 1945;"and James M.

Johnson, Francis L. Mark and Murray lellingz No.

2,514,954, issued July 11, 1950. The value of bonding the compositionmay be readily removed without reheating, which would be necessary ifthe bituminous composition were allowed to cool and solidify. .Theperiod tertiary amine group and an'amide group. However it is evidentthat on an equal weight basis the salts con-' has been found that thesalts are substantially more effective than the amides. Thus it has beenfound that a given improvement in bonding effectiveness can be achievedby using a quantity of the'salt that is significantly less than thequantity of the corresponding amide requiredv to yield the sameimprovement in bonding effectiveness. In like manner if two bituminouscompositions are prepared containing equal amounts by weight of theamide and its corresponding salt, the composition containing the saltexhibits a bonding effectiveness substantially superior to that of thecomposition containing the amide.

It has been thought that the effectiveness of compounds of this generaltype is due to the presence therein of a tain less of the tertiary amineand amide groups than do the corresponding amides. Hence the superiorityof the salts is a surprising and unexpected result.

Salts capable of being incorporated in bituminous compositions toachieve the advantages indicated above can be represented by thegeneral-formula:

wherein RC is an acyl radical of an acid selected from the groupconsisting of C12 to C fatty acids and rosin acids; A is an alkylenegroup containing 2 to 6 carbon atoms; R represents a hydrogen atom or analkyl group containing 1 to 4 carbon atoms; and R" represents an alkylgroup containing 1 to 4 carbon atoms. In the above general formula thetwo RCO groups and the two R" groups may be either the same or differentradicals. The salts defined by this general formula are believed to benew and are claimed herein as new compounds.

Typical compounds that come within the scope of the above formula andare useful in accordance with the present invention include:

named the rosin acid salts of N-(2-dimethylamino ethyl) oleamide,C17H33CONHCH2CH2CH2N (CH3 2.HOOCR named the rosin acid salts ofN-(3-dimethylamino propyl) oleamide,

C11H23CONHCH2CH2CI-IzN C3H'z 2.HOOCC17H33 named N- 3 -diisopropylarninopropyl) lauramide oleate,

C17H31CON CH3 CH2CH2N CH3) C3H7.HCOCC11H23 namedN-methyl-N(Z-methylisopropylamino ethyl) linoleamide laurate, and

named N-butyl-N-(4-dibutylamino butyl) oleamide oleate.

The salts of the present invention can be conveniently prepared byreacting an organic acid with a dialkylaminoalkylamine in either one ortwo steps. This is to say the amine can be first reacted with a limitedquantity of acid to form an amide and the amide then reacted with afurther quantity of the same or a different acid to form the salt; oralternatively, the amine may be mixed with a sufficient quantity of acidto form the salt in a single step.

Representative amines that can be used in this reaction include:(CHshNCHzCI-IzCHzNI-Iz named 3-dimethylamino propylamine,(CH3)2NCH2CH2NH2 named 2 dimethylaminoethylamine, (CH3)2NCH2CH2NHCH3named Z-dimethylaminoethyl methylamine,

(C4H9 2NCH2CH2CH2CH2NHC4H0 named 4-dibutylaminobutyl butylamine, and

C3H7 (CI-I3 NCHzCI-IzNI-ICI-Ia named 2-methylisopropylaminoethylmethylamine.

Representative of the organic acids that may be used are oleic,linoleic, linolenic, lauric, palmitic, stearic, rosin acids, abieticacid, the mixed acids of tall oil, or mixtures of any of these acids.Triglycerides, such as vegetable and fish oils and animal fats, may beused as ingredients to supply the fatty acids required in carrying outthe chemical preparation.

In cases where the salt is to be prepared in two steps, the amide can befirst prepared by mixing equimolar quantities of the organic acid anddialkylaminoalkylamine and heating at 109 to 200 C. in a suitablecontainer with suitable agitation. Upon mixing, the amine salt of theorganic acid is formed and during the heating process the salt ismolecularly dehydrated forming one mol of the N-dialkylaminoalkylamidewith the elimination of one mol of water, as follows: 1

Reaction on mixing:

The course of the reaction and its completion may be followed by notingthe diminishing proportion of carboxylic acid by titration with standardalkali and the diminishing proportion of titratable amine with standardacid. At the completion of the reaction there is substantially noorganic acid present and the titratable alkali has been reduced tosubstantially one-half of its original value. The measurement of theeliminated water may also be useful as a guide in determining thecompletion of the reaction.

In preparing the carboxylic acid salts of the N-dialkylaminoalkylamides,equimolecular proportions of the Ndialkylaminoalkylamide and the organicacid are mixed together at any suitable temperature at which thecomponents are liquids:

Alternatively, all reactions may be carried out concurrently by mixingone mol of dialkylaminoalkylarnine and two mols of organic acid andreacting the mixture at -200 C. in a suitable container with suitableagitation:

Surface active bonding agents prepared as described above may beutilized with any type of thermoplastic bituminous material, such aspetroleum derived asphalts, tars, natural asphalts, road oils, asphaltand tar cutbacks prepared with hydrocarbon diluents and pitches obtainedfrom all types of distillation or extraction residues. These surfaceactive agents are readily dispersed in bituminous materials when allcomponents are in the fluid state. For effective coating of wetaggregates with the treated-bituminous composition, the thermallystable, surface active agent is added in the proportions ofapproximately 0.1 to 2.0 parts by weight per 100 parts of bituminousmaterial.

Bituminous compositions incorporating the bonding agents of the presentinvention can be used in the preparation of paving compositionscontaining all of the usual types of aggregates such as gravel, crushedstone, sand or slag in either wet or dry condition. Also these agentsare useful in the coating or bonding with bituminous compositions ofother types of surfaces, such as metal, glass, wood, ceramics, plasticsand paper, particularly when the surface to be treated is wet, or whenthe treated material is to be exposed to water under conditions whichtend to cause a loss of strength of the bituminous bond.

In order to point out more fully the nature of the present invention thefollowing illustrativeexamples are given of typical methods of preparingthe amides and salts of the present invention.

Example 1 One part by weight of the product as thus prepared was mixedwith 100 parts by weight of asphalt cement at a temperature of 325 F.and maintained at this temperature for seven days. At the end of thisperiod the asphalt cement was mixed with petroleum naphtha in the properproportion to convert it to a cutback asphalt designated as RC-2. Thiscutback asphalt was mixed with wet aggregate to form a pavingcomposition and it was found that the asphalt readily coated all of theaggregate particles and upon curing formed a strong bond throughout themixture. When the paving composition was immersed in water it was foundto be completely resistant to separation of the bitumen from theaggregate particles.

A comparable product can be made by reacting one mol of the3-dirnethylamino propylamine and two mols of oleic acid as describedabove to form the oleic acid salt of N-(3-dimethylamino) propyloleamide.

Example 2 One mol of diethylarninoethylamine and two mols of oleic acidwere reacted as in Example 1. The resulting product, the oleic acid saltof N-diethylaminoethyl oleamide having the formula was a thermallystable bituminous bonding agent.

A comparable product can be made by reacting the diethylaminoethylamineand two mols of tall oil to form the rosin acid salts of theN-diethylaminoethyl tall oil fatty acid amide.

Example 3 One mol of 3-dimethylamino propylamine was mixed with one molof oleic acid and heated at 150-160 C. with constant agitation for fourhours. The resulting product was then mixed with one mol of rosin acidand agitated for a period of about 15 minutes to effect completereaction of the amide and the rosin acid to form the rosin acid salt ofthe amide. The product obtained was similar in its effectiveness to thatof Example 1.

Example 4 One mol of dimethylaminoethylamine and two mols of tall oilwere mixed and reacted as in Example 1, to yield rosin acid salts of thetall oil fatty acid amides of this amine. The resulting product was athermally stable, surface active bituminous bonding agent whichmaintained its effectiveness when dispersed in asphalt and likecompositions and kept at temperatures of 300-500 F. for several days.

Example 5 One mol of S-diethylamino propylamine and two mols of oleicacid were mixed and heated as in Example 1, to form the oleic acid saltof N-(3-diethylamino propyl) oleamide. This product was found to be athermally stable bonding agent when mixed with bituminous pavingmaterials and maintained at elevated temperatures.

A comparable product can be made by reacting one mol of this amine withtwo mols of tall oil to form a rosin acid salt of the tall oil fattyacid amide of this amine.

Example 6 One mol of 3-dibutylamino propylamine was reacted with twomols of oleic acid according to the procedure of Example 1, to form anoleic acid salt of N-(3-dibutylamino propyl) oleamide. This product whenincorporated in asphalt as described above was found to be a thermallystable bonding agent.

A comparable product can be made by reacting this Where RCO- is an acylgroup derived from a carboxylic acid selected from the group consistingof C12-C2o fatty acids and rosin acids; A is an alkylene groupcontaining from 2 to 6 carbon atoms; R is a radical selected from thegroup consisting of hydrogen and alkyl radicals con- .taining from 1 to4 carbon atoms; and R" is an alkyl group containing from 1 to 4 carbonatoms.

2. As new thermally stable compounds adapted to be incorporated inbituminous bonding compositions for coating wet aggregates, thecarboxylic acid salts as in claim 1 wherein at least one RCO- is derivedfrom a fatty acid containing 18 carbon atoms.

3. As new thermally stable compounds adapted to be incorporated inbituminous bonding compositions for coating wet aggregates, thecarboxylic acid salts as in claim 1 wherein at least one RCO- is derivedfrom rosin acids.

4. As new thermally stable compounds adapted to be incorporated inbituminous bonding compositions for coating wet aggregates, thecarboxylic acid salts as in claim 1 wherein the RCO- groups arev derivedfrom tall oil.

5. As new thermally stable compounds adapted to be incorporated inbituminous bonding compositions for coating wet aggregates, thecarboxylic acid salts as in claim 1 wherein the amide RCO- group isderived from a fatty acid containing 18 carbon atoms and the saltformingacid is a rosin acid.

6. As a new thermally stable compound adapted to be incorporated in abituminous bonding composition for coating wet aggregates, the rosinacid salt of the tall oil fatty acid amide of 3-dimethylaminopropylamine.

7. As a new thermally stable compound adapted to be incorporated in abituminous bonding composition for coating wet aggregates, the oleicacid salt of N-(S-dimethylamino propyl) oleamide.

8. As a new thermally stable compound adapted to be incorporated in abituminous bonding composition for coating wet aggregates, the oleicacid salt of N-(Z-diethylamino ethyl) oleamide.

9. As a new thermally stable compond adapted to be incorporated in abituminous bonding composition for coating wet aggregates, the oleicacid salt of N-(3-diethylamino propyl) oleamide.

10. As a new thermally stable compound adapted to be incorporated in abituminous bonding composition for coating wet aggregates, the rosinacid salt of the tall oil fatty acid amide of Z-dimethylaminoethylamino.

References Cited in the file of this patent UNITED STATES PATENTS2,419,404 Johnson Apr. 22, 1947 2,459,062 Cook et al. Jan. 11, 19492,514,954 Johnson et al. July 11, 1950 2,663,648 Jelling Dec. 22, 1953

1. AS NEW THERMALLY STABLE COMPOUNDS ADAPTED TO BE INCORPORATED INBITUMINOUS BONDING COMPOSITIONS FOR COATING WET AGGREGATES, CARBOXYLICACID SALTS CORRESPONDING THE GENERAL FORMULA: